System and method for multi-stage data logging

ABSTRACT

A multi-stage data logging system comprising a telecommunications stage for receiving, processing, and compressing data from one or more input channels, a recorder stage for storing said data to a memory device, a distribution stage for retrieving said stored data and distributing said data to one or more output channels, and a plurality of interface paths linking said three stages to one another. Different stages of the system can be located wide distances apart and the interface paths linking the three stages can be automatically switched to achieve fault tolerance of the system.

FIELD OF THE INVENTION

The present invention relates generally to data logging, and moreparticularly to a flexible and cost-effective multi-stage system andmethod for processing multi-channel input data with improved faulttolerance and flexible user access.

BACKGROUND OF THE INVENTION

The efficient storage and retrieval of multi-channel datacommunications, and especially of voice, are critically important inmany modem business and government applications. For example, financialinstitutions record instructions from clients as a protection againstfraud and as evidence in legal proceedings about the content oftelephone conversations; public safety agencies record emergency callsfor event reconstruction and future investigations; commercial entitiesmonitor transactions over the phone to evaluate salespersons'efficiency, to ensure customer satisfaction and to develop trainingprograms. There is a growing need for reliable recording of multiplechannels of multimedia information. These are but a few examples ofapplications in which it is necessary to efficiently store and process,usually at one location, multiple and frequently simultaneouscommunications from a large number of incoming data channels. Recentadvances in multimedia applications further dictate the necessity todevelop practical tools to efficiently process multiple channels inwhich incoming data can be in different formats, i.e., sound, images,data, etc. It is also apparent that with the proliferation of differentcommunications media, computer platforms and operating systems, a veryimportant practical aspect of all these applications is the ability toprovide seamless and efficient interface between the multi-channel datasystem and its users.

Thus, while capturing the incoming information remains the main functionof modem multi-channel data processing systems, other desirable systemfunctions, such as the efficient storage, indexing and retrieval ofrecorded communications, are becoming increasingly important.Preferably, all system functions should be transparent to the users,regardless of the data format, of the communications media or thespecific computer platforms being used. The present invention addressesthe need for such a data logging system and method and illustrates theiruse in practical applications.

Data logging systems for capturing and recording massive volumes of datatransmitted over multiple communication lines are known in the art. Atypical prior art data logging system, such as the one shown in FIG. 1,is implemented as a single physical unit performing most or all requiredfunctions, including telephone interface, signal processing, randomaccess buffering, and archive storage. In many practical applicationssuch implementation is perfectly adequate. Examples of such systems areprovided in, for example, U.S. Pat. Nos. 5,819,005; 5,448,420;5,446,603; 5,396,371; 5,339,203 and 4,827,461 to the assignee of thepresent application. These patents are hereby incorporated by referencefor all purposes.

However, as market needs change and performance demands increase,improved logger architectures have to be designed to support expandingcapacity requirements and emerging processing needs. Two strong marketdemands render prior art logger architectures at a disadvantage in thisregard: the need to increase the number of input ports, and the need toprovide simple and efficient access to the recorded information inplatform and media-independent ways.

Turning first to the input port requirements, modem data loggingapplications dictate the need to support an ever-increasing number ofinput channels. It should be apparent that as the number of channelsincreases so does the complexity of the processing system. The increasedcomplexity in turn creates at least two potential problems: (a)diminished fault tolerance of the system; and (b) practical constraintson the physical design, including the weight and size of the system, itswiring and power requirements, among others.

Increasing the system's complexity generally results in a greatervulnerability and higher risk of data losses because of the increasedprobability that one or more system components can malfunction. However,people of skill in the art would recognize that in many applications itis critically important that the operation of the system remainerror-free. Because of this stringent requirement and the fact that theinformation that loggers are entrusted to record is almost alwaysoriginal and ordinarily cannot be artificially regenerated, it isnecessary to build into the system sufficient redundancy so that themalfunction of one or more components would not lead to a shutdown ofthe entire system. This in turn makes it increasingly important todevise a scalable system that provides fault tolerant characteristicsregardless of the number of input channels.

Fault tolerant architectures that require additional “standby” hardwareto replace failed components are known in the art. One sucharchitecture, shown in FIG. 2, utilizes a local area network (LAN) 48for communication between loggers 44 and controller 46. Each logger isresponsible for recording communications on a plurality of input lines .In order to provide backup logging capabilities in the event a logger 44fails, spare loggers 42 are provided. In particular, each logger 44 isassociated with a spare logger 42 that is kept ready for use in theevent the working logger 44 fails. This fault tolerant architecture iswasteful and impractical, because it requires more space and twice thehardware (at twice the cost) of a comparable standard logger system.

An improved architecture of a fault tolerant system, shown in FIG. 3, isdescribed in an application by Yosef, EP 0822696A2, the content of whichis hereby incorporated by reference. The Yosef approach is to use asingle spare logger to back up a group of N loggers, thereby reducingthe hardware cost in the case when N≧2 compared with the system shown inFIG. 2. Notably, however, even in this improved prior art architecturethe spare unit is a completely functional device capable of performingall logging functions. Accordingly, it does not take advantage of thefact that in operation certain components of the logger fail much morefrequently than others. This is the case, for example, in componentswith physically moving parts, such as hard drives. In accordance withthe present invention cost savings are realized for the same faulttolerance level using separation of the logger into two or morefunctional stages, where higher redundancy is provided for thecomponents having higher failure rates. As illustrated below, using thisapproach it is possible to reduce the cost of the system considerably,without affecting its performance level.

As mentioned above, the increased complexity of the system also poseswiring, size and other practical problems. For example, an importantconsideration when installing a logger with a high number of inputchannels is the number of wires that interconnect the logger to the PBX.Thus, a logger having 128 input channels requires at least 256 wires.For practical reasons including susceptibility to picking up audibleelectrical noise over long cable runs, it is desirable to install thelogger next to or near the PBX. However, this location may not always beoptimal, desirable or even possible in practice. In particular, spatialconstraints as well as security issues pose serious problems. Thus, thelarge size of a high-capacity logger can make it impossible to installit in certain locations. It may further be costly and/or impractical torun massive cable bundles from the PBX room to the loggers. For securityreasons it may not even be desirable that the logger is anywhere nearthe PBX. It should thus be apparent that prior art systems implementedas single physical units suffer from some very serious practicalproblems. In accordance with the present invention, separation of thelogger into several functional stages provides the flexibility toperform different functions at spatially different locations, i.e., indifferent parts of the same building, city, or the world. In view of theabove, the potential advantages of this approach should readily beapparent.

In addition to the requirements for increased capacity, a whole new setof problems is created by the market demand for flexible playback ordata access to the stored information. In the context of thisapplication, access to the recorded data is referred to as data“distribution”. People of skill in the art will appreciate that it is byno means a trivial task to design a system capable of recording andprocessing multiple channels of information, while at the same timeproviding concurrent access to the recorded information from a largenumber of users. The task becomes even more complex if the users employdifferent computer platforms.

While many attempts have been made in the past to address these andother problems associated with prior art data logging, no adequatesolution has been proposed so far. The system and method of thisinvention overcome problems associated with the prior art and thus arebelieved to present significant technological advance. In particular,separation of the logger into several functional stages providesconsiderable flexibility in designing a functionally and ergonomicallyoptimized system for use in various practical applications. Further,distributing logger functions into separate physical stages leads tosignificant and unobvious advantages over the existing practice ofutilizing a single physical unit. For example, hardware for performingcertain functions in the same system can be bulky and thus inconvenientfor positioning at a particular location. Due to the functionalseparation approach of the present invention, however, bulky parts canadvantageously be placed where appropriate. Thus, the relatively bulkyrecording equipment capturing transaction information in the New YorkStock Exchange can be placed miles away from the crammed floor of theExchange. Additionally, in accordance with the principles of the presentinvention the design of the distribution stage enables users to accessthe recorded data at their convenience either real-time or at a laterpoint. Importantly, fault tolerance can be provided at a fraction of thecost associated with prior art approaches. The proposed approachprovides better system scalability, reliable performance at a low costand great flexibility in the retrieval of stored information comparedwith existing designs.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amulti-stage data logging system that overcomes problems associated withprior art solutions, and helps meet the market demands for increasedinput capacity, high distribution flexibility and fault tolerance.

In a preferred embodiment, the invention is a multi-stage data loggingsystem comprising: a telecom stage receiving input from a plurality ofinput channels; a recorder stage having one or more recorders, at leastone recorder storing data associated with input received from at leastone of said plurality of input channels; a distribution stage providingaccess to data stored in the recorder stage; a first interface linkingthe telecom and the recorder stages and a second interface linking therecorder and the distribution stages; wherein at least two stages of thesystem are physically separable and in operation can be located widedistances apart.

In a specific embodiment the telecom stage of the system furthercomprises a first interface capturing signals from said plurality ofinput channels; one or more signal processors converting capturedsignals into data having a predetermined format; and a second interfacefor transmitting said converted data to said recorder stage. Inembodiments where the input signal can be analog, the telecom stage ofthe data logging system further comprises at least one analog to digitalsignal converter.

In specific embodiments, the data logging system of the presentinvention provides data compression; time stamping of the receivedinput; authentication of signals from the input channels; and encryptionof the converted data.

In a preferred embodiment the data logging system of the presentinvention comprises an archive storage device, part of the recorderand/or telecom stages, for archiving data. In specific embodiments thisdevice can be fixed, such as a RAID array, or removable.

In another preferred embodiment, the recorder stage of the data loggingsystem comprises at least one backup recorder, and the system has meansfor detecting malfunctions in recorders of the recorder stage, and forautomatically switching interface links from the detected malfunctioningrecorder to the backup recorders. Related to this embodiment is anotheraspect of this invention, which is a method for operating a multi-stagedata logging system comprising: detecting a malfinctioning recorder inthe recorder stage; automatically switching interface links from thedetected malfinctioning recorder to a backup recorder to ensureuninterrupted operation of the system; and without disrupting theoperation of the system replacing the detected malfunctioning recorderwith a functioning recorder.

In yet another aspect, the invention is a method for increasing thecapacity of a multi-stage logger system comprising: without disruptingthe operation of the system attaching to a network-based orfour-wire-based interface between the telecom and the recorder stages atleast one recorder so that the combined capacity of the recorders in therecorder stage is equal to or exceeds a given number of channels; and/orattaching at least one additional telecom block to increase the inputchannel capacity of the system.

In another preferred embodiment, the present invention is a data logger,comprising: a telecommunication device receiving input from a pluralityof data sources; a processor converting input from said plurality ofdata sources to one or more data formats; a memory for storing converteddata corresponding to the received input from said plurality of datasources; a communication path; and a server transferring stored datafrom one or more of said plurality of data sources via the communicationpath to at least one remote user. In specific embodiments the server isa Web server and the communication path is the Internet.

In another aspect, the present invention is a method for accessinginformation in at least one digital logger storing data associated withinput from a plurality of input channels, comprising: at a Web serverhaving access to said at least one digital logger, receiving a requestfor retrieval of stored data from a client; retrieving stored data inaccordance with the received request; and transferring the retrieveddata to the client. In the specific embodiment covering voice inputchannels, the method further comprises accessing a record of an inputchannel made by a digital logger; or accessing call information for arecord of an input channel made by a digital logger.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a schematic diagram of a data logger of the prior artincorporating multiple logging functions in a single unit.

FIG. 2 is a schematic diagram of a logging system of the prior art,employing full operating redundancy where for each working logger thereis a spare logger;

FIG. 3 is a schematic diagram of a logging system of a prior artemploying one spare logger for each group of “N” working loggers.

FIG. 4 is a schematic diagram of a multi-stage data logging system inaccordance with a preferred embodiment of the present invention.

FIG. 5 is a block diagram of a multi-stage logging system configured inaccordance with a preferred embodiment of the present invention.

FIG. 6 is a schematic diagram illustrating another preferred embodimentof the multi-stage logger in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Prior Art

FIG. 1 is a schematic diagram of a prior art data logger 10. Logger 10incorporates an interface 14 for receiving data from input lines 12, ananalog/digital (A/D) and a digital/analog (D/A) signal converter 16 thatconverts analog signals from input lines 12 into digital signals whendata is flowing in one direction and digital to analog when the signalis flowing in the opposite direction. Interface 14 also communicateswith a speaker 17. The system further comprises a digital signalprocessor 18, generally used to compress the digital signals fromconverter 16; a controller 20, a buffer 22, and hard disc 23. In atypical implementation all components are located in a single physicalunit 13. As shown in FIG. 1, the unit may also include a storage unit24, such as a digital audio tape (DAT). The configuration and operationof a logger of the type illustrated in FIG. 1 is described in detail inseveral U.S. patents, including U.S. Pat. Nos. 5,819,005; 5,448,420;5,446,603; 5,396,371; 5,339,203 and 4,827,461 to the assignee of thepresent application, and which are incorporated herein by reference.

It will be appreciated by people of ordinary skill in the art that thenumber of input channels that can be handled by a logger of the typeshown in FIG. 1 is usually fixed by the design constraints of thephysical unit, i.e., by the number and the capacity of the interfacecards, the configuration of the processor 18, and others. Accordingly,to process a higher number of input channels it is generally necessaryto either increase the number of interface cards (limited by the numberof available slots) or duplicate the logger 10 one or more times, suchthat each unit handles a particular group of incoming channels. In theconfiguration shown in FIG. 1, as well as multi-logger architectures inwhich logger 10 is replicated to increase input channel capacity, usersmay encounter various problems of the type discussed in the backgroundpart of this application. For example, failure of one block in logger 10may disable the entire unit and thus jeopardizes the recording ofseveral input channels. Thus, the fault tolerance of the system dependson its weakest link, i.e., on the most failure-prone component of theunit. In many cases where no backup unit is provided the resulting faulttolerance is unacceptable. Further, space constraints may pose problemsbecause the standard design of the logger 10 as one physical unit doesnot allow its separation into functional blocks that can be placed inspatially optimal locations.

Reference is now made to FIG. 2, which is a schematic diagram of a priorart fault tolerant data logging system. Data logging system 40illustrated in FIG. 2 employs one spare logger 42 for each workinglogger 44. In a particular embodiment, each logger can be implemented asillustrated in FIG. 1 but other embodiments are possible, as known inthe art. In this architecture, all loggers are connected via a localarea network (LAN) 48 and upon failure of a working logger 44, the sparelogger 42 assigned to the failed logger is automatically activated.While just about any fault tolerant system will require some additional“standby” hardware to replace failed components, system 40 illustratedin FIG. 2 requires twice the hardware, at twice the cost, of aconventional system and in most cases is commercially impractical.

Reference is next made to FIG. 3, which is a schematic diagram of animproved fault tolerant data logging system of the prior art. System 50illustrated in FIG. 3 consists of one or more groups of “N” loggers 52connected via LAN 58, and linked by a group of “N” switches 60 to asingle spare logger 54. When one logger 52 fails, the switches 60automatically reroute data from the failed logger's input lines to thespare logger 54. For N≧2 this system requires less “standby” hardwarethan the prior art system of FIG. 2. Nevertheless, it is apparent thatsuch a design is suboptimal, at least because it does not make use ofthe fact that certain components of the logger are more reliable thanothers. Importantly, this and other prior art logger designs represent asingle-unit design philosophy that carries many performance limitationsas noted above.

The Present Invention

In contrast to the prior art designs described above, the approach takenin accordance with the present invention is to combine low-cost andhigh-reliability multi-stage recorders storing data from multiple inputdata channels with a powerful distribution technology that enablesplatform-independent access to the stored data from different physicallocations. Multiple channel data recording, and particularly voiceloggers, are known in the art. As shown above, some steps have alreadybeen taken to improve the reliability of such devices using redundancyapproaches. From the distribution perspective in the last few yearsInternet technology is becoming standard. However, to the best of thisinventor's knowledge, there is no suggestion in the past of combiningthese two paradigms in a multi-stage distributed logger, anext-generation product that brings together the most desirable featuresof these technologies.

In particular, loggers have been used in the past to record, index andstore large volumes of data from different input channels. However,practical limitations, such as their single-unit design, have limitedthe use of such loggers in many applications. With the distributedmulti-stage architecture of the present invention, at least thefollowing advantages over the prior art can be expected:

(a) highly reliable and low-cost data recording and storage due to anovel fault tolerant architecture in which failure-prone components areduplicated for redundancy;

(b) optimized use of space made possible by the physical separation ofthe logger in separate stages that allow, for example, placing bulkycomponents away from locations where their presence can be inconvenient(due to space limitations), or even highly undesirable (as in covertoperations);

(c) improved business models for information distribution.

Reference is now made to FIG. 4, which is a schematic diagram of amulti-stage data logging system in accordance with a specific embodimentof the present invention. In the illustrated embodiment, system 100consists of a telecommunications stage (“telecom stage”)102, recorderstage 104, and distribution stage 106. Broadly, the telecom stage servesto capture incoming signals, convert the captured signals in apredefined format, preferably digital, and perform certain processing onthe converted signals, usually in the nature of compression. Recorderstage 104 stores the processed input signals to a hard drive or similarlarge-capacity storage device, as well as in a buffer from which thedata can be forwarded to fixed or removable storage devices, which inthe embodiment shown in FIG. 4 are part of the distribution stage. Inaccordance with the present invention, the distribution stage serves notonly for access to the stored information but also for archivingpurposes. Importantly, individual functional stages of the system 100,such as those illustrated in FIG. 4, can be physically separated andtypically are housed in separate physical units.

It should be understood that FIG. 4 is merely an illustration of asystem built in accordance with the principles of the present inventionand should not be construed as a limitation of its design approach.Thus, functional separation of the logger into more than three stagescan be desirable in certain applications. In alternate embodimentsfunctional stages can be combined—for example, with reference to FIG. 4,the telecom and recorder stages on one hand, or the recorder anddistribution stages on the other hand can be implemented as singlephysical units. Furthermore, in alternative preferred embodiments datafrom the recorder stage is made available to users via a communicationsnetwork such as private communication lines, corporate intranets, theInternet or any combination thereof. It will be appreciated that suchnetworks can be accessed by various different computers, so that stage106 is “distributed” and would have no identifiable physical location.

In another aspect of this invention the stages of the system shown inFIG. 4 are connected using switch fabric 108 interfacing the telecom andrecorder stages on one hand, and the recorder stage and distributionstages of the system 100 on the other. It will be appreciated thatswitch fabric 108 interfacing different stages can be different indesign and implementation. In accordance with the present invention, theselection and design of the switch fabric 108 linking the individualstages of the overall system 100 are design parameters that allow forthe physical separation of the individual stages in accordance with thepreferred embodiments. In particular, dependent on the application, thestages of system 100 can be physically separated so that, for example,the telecom and recorder stages can be located in different parts of thesame room, in different rooms of the same building, in differentbuildings of the same town, in different towns or even differentcontinents. In a specific embodiment such wide spatial separation can beimplemented using, for example, standard public switched network accessarrangements, dedicated lines, or other communications media, as knownin the art. The individual stages of the system in accordance with thepresent invention are considered in more detail next.

The Telecom Stage

In accordance with the present invention telecom stage 102 generallyfunctions to capture and pre-process signals from a plurality ofcommunications lines into a format that is recognized by the recorderstage. As indicated above, in a preferred embodiment the communicationlines could be standard telephone lines, dedicated communication linesor other input data sources, which may transmit analog or digitalsignals. Regardless of their physical source or data format, in apreferred embodiment the captured input signals are digitized andcompressed, as known in the art. Naturally, different types of inputdata can be transformed into different internal formats, as instructedby the user.

More specifically, as shown in FIG. 4, telecom stage 102 incorporates afirst interface 110 for receiving signals from the input lines (notshown), which typically are telephone lines. In accordance with apreferred embodiment, interface 110 is designed for analog or digitalinput signals, or some combination thereof. When used with telephonelines, interface 110 generally is a high impedance interface that allowsfor passive tapping of the phone lines. In this embodiment interface 110employs voltage and/or current sensing to trigger recording ofcorresponding input channels. External triggering signals can also beused at the telecom stage, as known in the art. In the case of a digitalinput, interface 110 serves as a digital phone coupler, as known in theart. Various alternate embodiments of the interface 110 are known in theart and are described in detail, for example, in U.S. Pat. No. 4,827,461to Sander, which is incorporated herein by reference. It will beappreciated that interface 110 can be used for various additionalfunctions, such as beep generation, notching and others.

In the embodiment illustrated in FIG. 4, telecom stage 102 furthercomprises an AID signal converter 111 for digitizing the received analogsignals. Naturally, no such converter is required for purely digitalinputs. Stage 102 also comprises a digital signal processing (DSP) unit112 for processing signals digitized by converter 111 or supplieddirectly from digital input channels. In a preferred embodiment, DSPunit 112 is capable of handling various input data types, i.e., voice,image, facsimile and others. In a specific embodiment one processor 112is capable of handling various input data types and its processingalgorithm is selected dependent on the input data type. In alternativeembodiments, one processor can be used for each input channel so thatdifferent processing algorithms can be applied simultaneously todifferent input channels. It will be appreciated that whether one ormore processors are used, different data compression algorithms can beapplied to different input channels dependent on the data type, thestatistical distribution of the incoming data, and other factors. Suchprocessing algorithms are generally known in the art and will not beconsidered in further detail.

Telecom stage 102 illustrated in FIG. 4 further comprises controller 114that operates to direct and monitor the functions of the entire stage.Specifically, in a preferred embodiment, controller 114 directs theapplication of a particular processing algorithm by DSP processor 112 toa particular input data type. When instructed by the controller, in aspecific embodiment processor 112 is capable of performing DTMF signaldetection and decoding, and preferably also performs compression of thedata in accordance with well established standards. For example, in thecase of voice signal recording, the output of DSP processor 112 ispreferably made compatible with the G 723.1 and G 722 voice compressionstandards, which are known in the art.

In a specific embodiment, interface 110 and A/D converter 111 togetherwith a time slot assignment circuit (not shown) are implemented as alogger coupler card, that places the input data on a pulse codemodulation (PCM) highway (not shown) within the telecom stage 102. Inthis case the DSP unit 112 is directed by the controller 114 to processsignals in the appropriate time slots. In particular, controller 114reads the system clock, directs the assignment of time slots toindividual input channels, and provides a time stamp that is used in thecreation of individual channel records. As noted above, block 114 alsocontrols the operation of the DSP unit 112 and distributes datacompressed at its output to interface 116. In a preferred embodiment animportant function of the controller is to reconfigure the processingalgorithm(s) of the DSP unit 112 using downloaded software. Thus, in aspecific embodiment an input port (not shown) is provided for thecontroller to download instructions used to re-program the DSPprocessor(s) 112 from a personal computer (PC).

Finally, in a preferred embodiment telecom stage 102 comprises a secondinterface 116 for transmitting compressed data to the recorder stage104. In a specific embodiment the second interface 116 may be an E1 (2Megabit) transceiver or, for smaller applications, an RS-485 (1 Megabit)line. Other embodiments may be used, as known by those of skill in theart.

In accordance with the present invention, certain functions that are notrequired but are frequently useful in the operation of data loggers arealso provided in specific embodiments. Such functions include, forexample, time stamping, encryption and authentication of incoming data.Generally, authentication refers to mechanisms by which the transactingparties prove they are who they claim to be, i.e., in this context thatdata from an input channel indeed comes from a particular source;encryption usually refers to the altering of data so that it cannoteasily be read or modified, if intercepted. If used, such functionsshould be placed as close as possible to the source of the informationthat is being captured—and accordingly are implemented in the system ofthis invention as part of the telecom stage 102. In a specificembodiment, these functions are implemented by the controller block 114.Other functions of the telecom stage can be implemented in specificembodiments, as known in the art. Thus, for example, in a specificembodiment telecom stage 102 can provide lightning protection and can beused to detect DTMF signals, to identify caller IDs, to detect thepresence or absence of voice in a particular input channel, andcorrespondingly control a trigger mechanism for use by the recorderstage 104. As known in the art, the telecom stage can also be used as acurrent and/or voltage sensor. Functions described in this paragraph canbe implemented as part of the logger coupler card used in a specificembodiment, and/or the DSP unit 112 of the telecom stage 102.

It will be appreciated by people of ordinary skill in the art that ingeneral the components of the telecom stage are robust and in particularinvolve no physically moving parts. Accordingly, in a preferredembodiment, they need not be duplicated in fault-tolerant architecturesbuilt using the principles of the present invention. Naturally, in verysensitive applications where there is little or no margin of error thetelecom stage can also be duplicated with a standby unit, as shown inFIG. 6. However, in accordance with the present invention, a singlestandby telecom stage can be used to serve as backup of N recorderstages in a manner similar to that illustrated in FIGS. 3 and 6. Thecost savings compared with the architecture shown in FIGS. 2 and 3 arereadily apparent.

Finally, since telecom stage 102 is separated from the remainingcomponents of the logger by switch fabric 108, the stage can beimplemented in a separate physical unit having as many input channelslots as desired. This compares favorably to the standard single-unitlogger design, in which the number of input channels is limited by thenumber of available slots on the circuit board, which in turn arelimited by the overall dimensions of the unit. It will be appreciatedthat the multi-stage design used in accordance with the presentinvention thus extends the input channel capacity of the logger.

The Recorder Stage

Again with reference to FIG. 4, recorder stage 104 of the logger storesinput from the telecom stage to a hard drive or a suitablelarge-capacity random access storage device, as well as in a buffer fromwhich the data can be forwarded to fixed or removable storage devices.In a particular embodiment directed to storing voice records, thefunction of recorder stage 104 can be described broadly as creatingvoice files and providing an associated database with stored callinformation. To this end, the recorder stage 104 in a preferredembodiment has the ability to create new voice records, merge callrecords and establish a database with call information for each createdrecord. In a preferred embodiment, newly created records, along withidentifier information are stored in a database at unique recordaddresses.

In accordance with the embodiment illustrated in FIG. 4, recorder stage104 has the following components: (a) an interface 120 receiving inputfrom the telecom stage; (b) a controller 122 directing and monitoringthe recorder stage operations, and generally comprising a microprocessorwith memory; (c) an elastic buffer 124 for transitional data storage;(d) a hard disk or similar large-capacity storage device 126 for datastorage (2 Gigabytes minimum); and (e) a second interface 128 forconnection to the distribution stage. It will be appreciated that whilethe components of the recorder stage are illustrated in FIG. 4 as beingseparate, they need not be implemented in separate physical units.

The function and operation of the recorder stage 104 is generally knownin the art. For example, it is described in U.S. Pat. Nos. 5,819,005;5,448,420; 5,446,603; 5,396,371; 5,339,203 and 4,827,461 to the assigneeof the present application, which are hereby incorporated by referencefor all purposes. It will be appreciated that alternate embodimentsemploying different storage media or internal architecture can be used,if necessary. For the purposes of this invention, it is important tonote two main differences from prior art designs. The first differenceis due to the flexible platform-independent data access provided inaccordance with the present invention to end users in the distributionstage. To support such an access, when viewed from the distributionstage the recorder of this invention appears as a file server providingaccess to a plurality of records (from input data sources) stored in adatabase at unique record addresses. The server preferably supportsdifferent data transfer protocols. The second difference is that sincethe recorder stage uses moving physical parts and is thus prone tomalfunctioning, for high reliability in accordance with this inventionit is desirable to provide backup units of the N recorders (or criticalcomponents thereof) of the recorder stage. These two aspects of thepresent invention are described in further detail next.

In accordance with a preferred embodiment, recorder stage 104 hasoperating system that supports different file access protocols, such asMicrosoft's SMB, the UNIX-based NFS and the standard FTP file transferprotocols. Thus, when viewed from the distribution stage 106, therecorder in a preferred embodiment appears as a server supporting theseand possibly other file transfer protocols, in which records thatcorrespond to different input channels appear to the user as separatefiles having unique record addresses. In a preferred embodiment, thesefiles are identified by the call record information and contain, forexample, information about the caller ID, the date and time of thecommunication, its duration, and others. With reference to FIG. 6, auser at a PC 106 connected to the recorder stage via communications path258 and operating, for example, in a Microsoft Windows environment canclick on a “Network Neighborhood” icon on his computer to locate arecorder 202 of interest. As noted above, various records in such arecorder would appear as files that are viewable using Microsoft's SMBprotocol. Once a desired record is identified, it can be “dragged” tothe user's computer for playback. Similarly, a NFS or Linux client canaccess files at a recorder that supports the corresponding UNIX-basedprotocol. Further, file transfers from the recorder can be accomplishedover a network 260, such as the Internet, using the well-known FTPprotocol. Naturally, security can be implemented at the recorder end, ifdesired, as known in the art. In each case, it is important that fromthe viewpoint of the user the recorder stage appears as a serveraccessing different files organized in such a manner as to provide theuser with access to unique records from different input channels.

Focusing next on the fault-tolerant aspect of this invention, FIG. 4illustrates a recorder stage with a single recorder. As noted above,however, in many practical applications the recorder stage can have twoor more recorders, each processing information about a particular set ofinput channels. Furthermore, in terms of the fault-tolerant aspect ofthe present invention and with reference to FIGS. 2, 3 and 6, it isnoted that unlike the system's telecom stage, the recorder stagetypically comprises physically moving parts, and thus is prone tooccasional malfunction. Accordingly, in a specific embodiment of thepresent invention shown in a diagram form in FIG. 6, the recorder stageis implemented in a single physical unit in what is known as a “hotswapping” M×N design. In this design one backup recorder unit 254 isused for every N working units 252, and switchover to the backup unitoccurs automatically without turning off the power. In a specificembodiment, N recorders implemented as swappable modules are physicallyplaced in drive bays of a physical unit and can be replaced, ifnecessary, without turning off the power of the unit. Detection of arecorder malfunction and control over the entire stage is provided bythe controller 256, as known in the art. Schematically, the architectureof the fault-tolerant embodiment of the present invention resembles thearchitecture in FIG. 3, the important difference being that instead ofusing an entire backup logger, the system of the present invention usesas duplicate hardware merely the recorder stage or components thereof,such as the hard disk 106. Such a design approach not only provides thedesired performance level and fault tolerance but also results inconsiderable savings in terms of the overall system cost.

Providing automatic switchover without disrupting the operation of thesystem, as described, is an important aspect of the present invention.This feature is made possible by the selection, in a preferredembodiment, of network or 4-wire interfaces linking individual stages ofthe logger system, which enables inserting or taking out systemcomponents without affecting the operation of the entire system. It willbe appreciated that the same feature would be difficult to provide withPC bus interfaces. Further, it will be appreciated that this selectionof the interface links also makes it possible to incrementally addrecording capacity simply by attaching to these links of additionaltelecom blocks, recorders or both. Clearly, this incremental additioncan also be done without interrupting the operation of the system, whichfeature of the present invention is perceived to have significantpractical utility.

The Distribution Stage and Switch Fabrics

In accordance with the present invention a very flexible approach istaken to the design of the distribution stage of the logger. Generally,the distribution stage serves for retrieval of recorded information andproviding it in a humanly recognizable form, i.e., as an image, aprintout, a sound clip or others. In a preferred embodiment, thedistribution stage also serves for archiving the recorded information toa removable storage, such as magnetic tape, magnito-optical storagedevice, DVD, or others.

As best seen in FIG. 6, in a preferred embodiment the distribution stagemay have no single physical location, and in this sense is truly“distributed”. As seen in this figure, one or more recorders 252 areattached to a communication path 258. This path can provided usingEthernet, optical fiber or other media. It may be part of a local areanetwork (LAN), a wide area network (WAN), and preferably has access tothe Internet. In a specific embodiment, the communication path isimplemented as a Universal Serial Bus (USB). It is foreseen that thecommunication path may also be part of a storage architected network(SAN). As seen from the above list of options, there is no limitation onthe type of communication path provided at the back end of the recorderstage, which path concurrently serves as part of switch fabric 108 (seeFIG. 4).

With reference to the specific embodiment illustrated in FIG. 4, thedistribution stage also has a controller 132 for directing andmonitoring distribution stage operations, a buffer 134 for transitionaldata storage, and a second interface 136 for distributing data to one ormore output channels. Distribution stage 106 in the embodimentillustrated in FIG. 4 may also include an archive storage device 137 forarchiving data, which can be either fixed (such as a RAID array) orremovable. In one embodiment, this archive storage device 137 is a DVDRAM drive, a digital audio tape (DAT), or any suitable device capable ofstoring large volumes of data from multiple recorders of the recorderstage 104. In an alternate embodiment, the archive drive is part of therecorder stage, not the distribution stage. As seen, in this“OEM-friendly” embodiment, users may be free to design their owncustomized distribution stage.

With reference to FIG. 6, in a preferred embodiment, the distributionstage is implemented using at least in part Web server designtechnology. This approach has the advantage of using a powerfuldistribution tool, which is well known and can readily be employed tosupport a number of users regardless of their specific computerplatforms. In this sense, the Web server 280 acts as an intermediarybetween one or more recorders 252 in the recorder stage of the logger,and the users accessing the stored information via, for example, theInternet. As noted in the preceding section, in accordance with thepresent invention the recorder stage will make records from differentinput channels available as files that are stored at unique recordaddresses and are made accessible to the Web server 280. In this contextit should be noted that in a preferred embodiment the Web server used inthe present invention has built-in archiving functions.

In accordance with the present invention Web server 280 may beimplemented using any computer, such as, for example, a SUN work stationusing the UNIX operating system and running a web server program thatpreferably accepts requests for information framed according to asuitable protocol, such as the HyperText Transport Protocol (HTTP) or aversion of it that supports public-key-based authentication orencryption. In response to these requests, Web server 280 accesses theloggers records directly, or it causes a process to access data in adatabase of the recorder stage through a common gateway interface (CGI);and sends the requested files to the requesting client according to theclient's Internet address which, in one embodiment, may be providedaccording to the Transmission Control Protocol, Internet Protocol(TCP/IP). In a specific embodiment, access to the server can be providedafter going through a firewall (not shown) for added security. It willbe appreciated that similar distribution scheme can be provided as partof a corporate intranet.

In a specific embodiment employing a Web server as part of thedistribution stage users 208 access the Web server through a browser oranother suitable application that can playback audio files, in the caseof recorded voice information, or display data in a generic case.Specifics of the file formats or data transmission protocols aregenerally known in the art and need not be described in further detail.

Reference is now made to FIG. 5, which is a block diagram of amulti-stage logging system configured in accordance with a preferredembodiment of the present invention. A wide area network (WAN) 200, suchas the Internet or alternatively an Intranet, links a series ofrecorders 202 located in various different cities, todistribution/archiving engines 204 and 206, located in principal citieslike Los Angeles and New York, respectively. A series of user computers208, possibly located in different cities, is also connected to WAN 200and can access data recorded by recorders 202 and stored in archivedrives 204 and 206. In this configuration, agents located in offices, oreven their own homes, in different cities throughout the world canaccess data logged by equipment physically located thousands of milesaway.

As noted above, with reference to FIG. 4 each stage of the logger inaccordance with the present invention is designed so that the switchfabric units 108 can be used not only to provide physical separation ofthe individual stages of the logger, but also to achieve fault toleranceof the system by isolating failed components and switching operation toproperly functioning standby units. Numerous configurations arepossible, as illustrated in exemplary embodiments above.

Low cost components and switch fabric design also allow for faulttolerant capability in a scalable fashion. To demonstrate the faulttolerant characteristics of a typical configuration, consider a recorderstage comprised of eight working recorders and three “spare” recorders.Assuming a 2 Megabit (4 wire) interface linking the recorder stage withthe telecom and distribution stages, the eight recorders would be linkedto the three spares via a 32×12 switch matrix ((8 working recorders×4wires)×(3 spare recorders×4 wires)). In the event of a recorder failure,the recorder controller would route the failed recorder's input to aspare recorder via the switch matrix. The cost savings compared with thecase of duplicating entire units are readily apparent.

The advantages of the data loggers built in accordance with the presentinvention are illustrated in the following examples:

EXAMPLE 1

One of the advantages of the multi-stage distributed logger of thepresent—invention—its design flexibility—is clearly illustrated by itsuse in stock or commodities exchanges. Financial institutionsrepresented at such exchanges record instructions from clients as aprotection against fraud and as evidence in legal proceedings about thecontent of telephone conversations. Therefore, it is highly desirablethat data loggers be provided to record communications between brokersat the exchange floors and their clients. As known, however, there isalways a concern about the space on the trading floors. This concern isspecifically addressed by the multi-stage design of the logger inaccordance with the present invention, in which only the telecom stageelectronics would need to be located physically on the trading floor.The recorder stage and various distribution servers of the logger couldbe located physically either someplace more convenient in the building,or in fact someplace else in the city or the world. For example, an Eltwisted pair interface can stretch approximately 2000 feet, so withavailable “repeaters” the separation distance between the telecom andthe remaining stages is virtually unlimited. Since the voice compressionfunction is performed in a preferred embodiment in the telecom stage,use of the public switched network (or private) facilities would beoptimized. Importantly, the telecom stage can apply encryptionalgorithms so that data coming out of the exchange floor is protectedagainst unscrupulous use. It will be appreciated that the same advantagecan be used, for example, by law enforcement agencies that are entitledto have wiretap access to phone lines, but until now did not have amechanism to protect themselves by encryption from being wiretappedthemselves.

Furthermore, it can be appreciated that the multi-stage design of thelogger in accordance with the present invention enables considerablysimplified disaster recovery procedures, since destruction or simplyfailure of any single component would not affect the function of theentire system. In addition, since the present invention separates thetelecommunications electronics from the recorder, cabling to therecorder can easily be reduced. Such cabling reductions may range from15:1 to 200:1. The net result is lower installation costs and thesatisfaction of any political concerns regarding system location andsecurity.

EXAMPLE 2

In this example it is shown how the multi-stage design of the datalogger in accordance with the present invention can be used to createand implement new business models. Assume for example that a data loggeris used by a police to monitor 911 calls in a particular area.Information about such calls is generally available to the interestedpublic, for example the news media, but so far has been used in only afew cases primarily because of the difficulties associated with theaccess to such information. Using the distributed design of a logger inaccordance with the present invention, however, it would be a simplematter to make such records available to the public immediately,possibly for a fee.

In particular, a Web server run by the police can store or be givenaccess to data files corresponding to individual 911 calls. Withreference to FIG. 6, an authorized user may utilize a personal computerto access the police logger over the world wide web (WWW) of theInternet at a predetermined URL. The user's computer may be runningstandard web browser, such as the NETSCAPE browser. As soon as thecomputer is connected to Web server 280 a computer process startscommunicating with the user through the web browser. In particular, aservice routine may be initiated causing a “home page” to be displayed,which greets the user, and describes the service provided by system.Next, Web server 280 elicits user information, including a useridentification (ID), password and other administrative data necessaryfor ensuring that the user is an authorized user. Next, the audiofile(s) corresponding to individual 911 call records can be displayed tothe user who can then select a file. As known in the art, variousprotocols exist for the playback of audio files over the Internet. Bymeans of an example, the user can be provided with a File Headerinformation defining the audio files in fields such as: (1) File name;(2) Date created; (3) Size in bytes; (4) Audio file types in use; (5)Total associated files; (6) a command set code; and others.Additionally, instructions may be provided for decompressing anddecoding a specific or proprietary Audio Player software (possiblyresiding on the Web server), on how to play the files, includinghyperlinks, etc. Various levels of access protection can be implemented,as known in the art, so that access hierarchy can be established fordifferent groups of users.

It should be apparent that the use of the logger along the linesdescribed in Example 2 creates the possibility of a completely new andheretofore unused business model.

While the foregoing has described and illustrated aspects of variousembodiments of the present invention, those skilled in the art willrecognize that alternative components and techniques, and/orcombinations and permutations of the described components andtechniques, can be substituted for, or added to, the embodimentsdescribed herein. It is intended, therefore, that the present inventionnot be defined by the specific embodiments described herein, but ratherby the appended claims, which are intended to be construed in accordancewith the following well-settled principles of claim construction: (a)Each claim should be given its broadest reasonable interpretationconsistent with the specification; (b) Limitations should not be readfrom the specification or drawings into the claims (e.g., if the claimcalls for “antenna”, and the specification and drawings show a coil, theclaim term “antenna” should not be limited to a coil, but rather shouldbe construed to cover any type of antenna); (c) The words “comprising”,“including”, and “having” are always open-ended, irrespective of whetherthey appear as the primary transitional phrase of a claim or as atransitional phrase within an element or sub-element of the claim; (d)The indefinite articles “a” or “an” mean one or more; where, instead, apurely singular meaning is intended, a phrase such as “one”, “only one”,or “a single”, will appear; (e) Words in a claim should be given theirplain, ordinary, and generic meaning, unless it is readily apparent fromthe specification that an unusual meaning was intended; (f) an absenceof the specific words “means for” connotes applicants' intent not toinvoke 35 U.S.C. §112 (6) in construing the limitation; (g) Where thephrase “means for” precedes a data processing or manipulation“function,” it is intended that the resulting means-plus-functionelement be construed to cover any, and all, computer implementation(s)of the recited “function”; (h) a claim that contains more than onecomputer-implemented means-plus-function element should not be construedto require that each means-plus-function element must be a structurallydistinct entity (such as a particular piece of hardware or block ofcode); rather, such claim should be construed merely to require that theoverall combination of hardware/firmware/software which implements theinvention must, as a whole, implement at least the function(s) calledfor by the claim's means-plus-function element(s); (i) ameans-plus-function element should be construed to require only the“function” specifically articulated in the claim, and not in a way thatrequires additional “functions” which may be described in thespecification or performed in the preferred embodiment(s); (j) Theexistence of method claims that parallel a set of means-plus-functionapparatus claims does not mean, or suggest, that the method claimsshould be construed under 35 U.S.C. §112 (6).

I claim:
 1. A multi-stage data logging system comprising: a) atelecommunications (“telecom”) stage receiving input from a plurality ofcommunication channels; b) a recorder stage having one or morerecorders, at least one recorder logging data associated withinformation transmitted on at least one of said plurality ofcommunication channels; c) a distribution stage providing access to datalogged in the recorder stage; d) a first interface linking the telecomand the recorder stages and a second interface linking the recorder andthe distribution stages; wherein at least two stages of the system arephysically separable and in operation can be located wide distancesapart.
 2. The data logging system of claim 1 wherein the telecom stagecomprises: a1) a first interface capturing signals from said pluralityof communication channels; a2) one or more signal processors convertingcaptured signals into formatted data; and a3) a second interface fortransmitting said converted data to said recorder stage.
 3. The datalogging system of claim 2 wherein said one or more data processorsprovide data compression.
 4. The data logging system of claim 2 whereinsaid one or more data processors encrypt the converted data.
 5. The datalogging system of claim 2 wherein the telecom stage further comprises atleast one of: analog to digital signal converter and means formonitoring digital telephones.
 6. The data logging system of claim 1wherein the telecom stage provides time stamping of the received input.7. The data logging system of claim 1 wherein the telecom stage providesauthentication of signals from said plurality of input channels.
 8. Thedata logging system of claim 1 wherein the recorder stage comprises acontroller for directing and monitoring recorder stage operations, andeach recorder comprises: b1) a first interface receiving data from thetelecom stage; b2) a buffer for transitional data storage; b3) a randomaccess storage device for data storage; and b4) a second interface fortransmitting stored data to the distribution stage.
 9. The data loggingsystem of claim 8 wherein the recorder stage still further comprises anarchive storage device for archiving data.
 10. The data logging systemof claim 8, wherein the random access storage device is a hard disk. 11.The data logging system of claim 9 wherein said archive storage deviceis fixed.
 12. The data logging system of claim 9 wherein said archivestorage device is a RAID array.
 13. The data logging system of claim 9wherein said archive storage device is removable.
 14. The data loggingsystem of claim 1 wherein the distribution stage comprises: c1) a firstinterface receiving data from the recorder stage; c2) a controller fordirecting and monitoring distribution stage operations; c3) a buffer fortransitional data storage; and c4) a second interface for distributingdata to one or more output channels.
 15. The data logging system ofclaim 1 wherein the distribution stage comprises an archive storagedevice for archiving data.
 16. The data logging system of claim 15wherein said archive storage device is fixed.
 17. The data loggingsystem of claim 15 wherein said archive storage device is a RAID array.18. The data logging system of claim 15 wherein said archive storagedevice is removable.
 19. The data logging system of claim 1 wherein thedistribution stage comprises: an operating system software applicationand a computer capable of running said software application andaccessing one or more remote serve computers.
 20. The data loggingsystem of claim 19 wherein said computer is connected to said one ormore remote server computers via a local area network.
 21. The datalogging system of claim 19 wherein said computer is connected to saidone or more remote server computers via an Internet protocol (I/P)network.
 22. The data logging system of claim 1 wherein the recorderstage comprises at least one backup recorder, and the system furthercomprises means for detecting a malfunction in a recorder of therecorder stage, and means for automatically switching interface linksfrom the detected malfunctioning recorder to said at least one backuprecorder.
 23. The data logging system of claim 1 wherein at least one ofsaid first and second interfaces is network-based.
 24. The data loggingsystem of claim 1 wherein at least one of said first and secondinterfaces is a four-wire interface.
 25. The data logging system ofclaim 1, wherein the telecom stage comprises at least one of: voltagesensing, current sensing or external signals to trigger recording ofdata from a communication channel.
 26. The data logging system of claim1, wherein input from the plurality of communication channels comprisesone or more of: voice, image or facsimile data types, and said one ormore data processors are configured to process said data types.
 27. Thedata logging system of claim 26, wherein output of said one or more dataprocessors is compatible with the G 723.1 or G 722 international voicecompression standards.
 28. The data logging system of claim 26, whereinsaid one or more data processors are re-programmable.
 29. The datalogging system of claim 1, wherein input from different communicationchannels is stored as a plurality of files having unique recordaddresses.
 30. The data logging system of claim 29, wherein each filehas associated call record information.
 31. The data logging system ofclaim 29, wherein the recorder stage is implemented as a serversupporting a plurality of file access protocols.
 32. The data loggingsystem of claim 1, wherein the distribution stage is implemented as anetwork server.
 33. The data logging system of claim 32, wherein thenetwork server is a Web server.
 34. The data logging system of claim 32,wherein the network server is a file server.
 35. The data logging systemof claim 33, wherein users can access the Web server through a browser.36. The system of claim 1, wherein at least two stages are located indifferent rooms of the same building.
 37. The system of claim 1, whereinthe recorder stage and the distribution stage are located in differentcities.
 38. A multi-stage data logging system comprising: a) a firstmeans for receiving signals from one or more communication channels; b)a second means for logging data associated with received signals; c) athird means for retrieving logged data and distributing retrieved datato one or more output channels; wherein at least two of said first,second, and third means are physically separable and can operate widedistances apart.
 39. The data logging system of claim 38 furthercomprising an archive storage device for archiving data from said one ormore communication channels.
 40. The data logging system of claim 38wherein received signals from said one or more communication channelsare voice signals, and the second means further comprises means forrecording call information about the received voice signals.
 41. Thedata logging system of claims 1 or 38 wherein linking of at least one ofthe telecom and recorder stages, and recorder and distribution stages isprovided over a communications network.
 42. The data logging system ofclaim 41, wherein the communications network is one or more of: privatecommunication lines, public switched telephone network, corporateintranet, the Internet or a combination thereof.
 43. A data logger,comprising: a telecommunication device receiving input from a pluralityof communication channels; a processor converting the received input toone or more data formats; a memory for logging information about thereceived input, the information comprising data converted to at leastone data format; a communication path to a communications network; and aserver having access to the memory via the communications network fortransferring logged data from one or more of said plurality ofcommunication channels via the communications network to at least oneremote user.
 44. The data logger of claim 43 wherein the server is a Webserver and the communications network is the Internet.
 45. A method foroperating a multi-stage data logging system having: a telecom stagereceiving input from a plurality of channels; a recorder stage havingtwo or more recorders, at least one recorder storing data associatedwith input received from the plurality of channels and at least onebackup recorder; a distribution stage providing access to data stored inthe recorder stage; and a first interface linking the telecom and saidone or more recorders of the recorder stages and a second interfacelinking the recorder and the distribution stages; the method comprising:detecting a malfunctioning recorder in the recorder stage; automaticallyswitching interface links from the detected malfunctioning recorder tosaid backup recorder to ensure uninterrupted operation of the system;and without disrupting the operation of the system replacing thedetected malfunctioning recorder with a functioning recorder.
 46. Amethod for increasing the recording capacity of an operating multi-stagedata logging system having: a telecom stage having telecom blockscapturing input from at most N input channels; a recorder stage havingone or more recorders, said recorders having maximum recording capacityof M (M≦N) channels; a distribution stage providing access to datastored in the recorder stage; a first network-based or four-wire-basedinterface linking the telecom and the recorder stages; and a secondinterface linking the recorder and the distribution stages; the methodcomprising: (a) without disrupting the operation of the system attachingto said first interface at least one recorder so that the combinedcapacity of the recorders in the recorder stage is equal to or exceeds Nchannels (b) without disrupting the operation of the system, attachingto said first interface at least one additional telecom block so thatthe system can capture P>N input channels; and (c) repeating step (a)until the combined capacity of the recorders in the recorder stage isequal to or exceeds P channels.